Interactive input systems that allow users to inject inputs such as digital ink, mouse events, text or the like into a computer program typically utilise an input method such as an active pointer (e.g. a pointer that emits light, sound or other signal) or a passive pointer (e.g., a finger, cylinder or other object). Alternatively these same inputs may be inputted via another suitable input device such as a mouse or trackball. These more conventional forms of input are less interactive compared to new interactive input systems using active or passive pointers. These interactive input systems include but are not limited to: touch systems comprising touch panels employing analog resistive or machine vision technology to register pointer input such as those disclosed in U.S. Pat. Nos. 5,448,263; 6,141,000; 6,337,681; 6,747,636; 6,803,906; 7,232,986; 7,236,162; and 7,274,356 and in U.S. Patent Application Publication No. 2004/0179001, all assigned to SMART Technologies ULC of Calgary, Alberta, Canada, assignee of the subject application, the entire disclosure of which are incorporated herein by reference; touch systems comprising touch panels employing electromagnetic, capacitive, acoustic or other technologies to register pointer input; tablet and laptop personal computers (PCs); personal digital assistants (PDAs) and other handheld devices; and other similar devices.
In any interactive input system requiring physical interaction with a display, there exists a common problem of determining the exact location of the physical interaction. This is particularly prevalent in touch systems where the physical contact of an active or passive pointer upon a display is intended to trigger an event on an attached computer system. The method of detecting the presence of a contact is unique to the technology employed in the interactive input system, in interactive input systems utilizing an optical or other vision based technology, the method is typically analyzing the output of an imaging device to determine the location of a pointer within the field of view of the imaging device.
A further hindrance to determining the exact location of a physical interaction with a display in an optical based interactive input system is the presence of unwanted contact with the display. For example, if a user is intending on touching the display with a finger in order to generate a touch event, the user may inadvertently also press on the display with the palm of their hand, or the sleeve of their shirt may contact the display. Either of these occurrences would generate touch events in the system which are not intended by the user, and would significantly reduce the functionality of the system.
Accordingly, improvements in interactive input systems to facilitate a greater number of true contacts are desired. It is therefore an object to provide a novel method for providing assistance in the detection and rejection of contact events in interactive input systems and a novel interactive input system employing the same.